Materials are produced today using a range of processes ranging from time intensive outdoor growth and harvesting to energy intensive factory centric production. As demand for raw goods and materials rise, the associated cost of such materials rises. This places greater pressure on limited raw materials, such as minerals, ores, and fossil fuels, as well as on typical grown materials, such as trees, plants, and animals. Additionally, the production of many materials and composites produces significant environmental downsides in the form of pollution energy consumption, and a long post use lifespan.
Conventional materials such as expanded petroleum based foams are not biodegradable and require significant energy inputs to produce in the form of manufacturing equipment, heat and raw energy.
Conventionally grown materials such as trees, crops, and fibrous plants, require sunlight, fertilizers and large tracts of farmable land.
Finally, all of these production processes have associated waste stream whether they are agriculturally or synthetically based.
Fungi are some of the fastest growing organisms known. They exhibit excellent bioefficiency, of up to 80%, and are adept at converting raw inputs into a range of components and compositions. Fungi are composed primarily of a cell wall that is constantly being extended at the tips of the hyphae. Unlike the cell wall of a plant, which is composed primarily of cellulose, or the structural component of an animal cell, which relies on collagen, the structural oligosaccharides of the cell wall of fungi relay primarily on chitin. Chitin is strong, hard substance, also found in the exoskeletons of arthropods. Chitin is already used within multiple industries as a purified substance. These uses include: water purification, food additives for stabilization, binders in fabrics and adhesives, surgical thread, and medicinal applications.
Given the rapid growth times of fungi, its hard and strong cellular wall, its high level of bioeffciency, its ability to utilize multiple nutrient and resource sources, and, in the filamentous types, its rapid extension and exploration of a substrate, materials and composites, produced through the growth of fungi, can be made more efficiently, cost effectively, and faster, than through other growth processes and can also be made more efficiently and cost effectively then many synthetic processes.
Numerous patents and scientific procedure exists for the culturing of fungi for food production, and a few patents detail production methods for fungi with the intent of using its cellular structure for something other than food production. For instance U.S. Pat. No. 5,854,056 discloses a process for the production of “fungal pulp”, a raw material that can be used in the production of paper products and textiles.
Accordingly, it is an object of the invention to provide a method for the culturing of filamentous fungi specifically for the production of materials and composites composed in part, or entirely of, hyphae and its aggregative form, mycelia and mycelium.
Briefly, the invention provides a method for producing grown materials and, in particular, provides a method of using the growth of an organism to produce materials and composites.
In accordance with the invention, a fungi is cultured for the production of a material using the vegetative phase of the fungi.
This method uses the growth of hyphae, collectively referred to as mycelia or mycelium, to create materials composed of the fungi cellular tissue. This method expressly includes the growth of hyphae to create composites, utilizing particles, fibers, meshes, rods, elements, and other bulking agents, as a internal component of the composite, where the hyphae and other cellular tissue and extra cellular compounds act as a bonding agent and structural component.
In one embodiment, the method of making a composite material comprises the steps of forming an inoculum including a preselected fungus; forming a mixture of a substrate of discrete particles and a nutrient material that is capable of being digested by the fungi; adding the inoculum to the mixture; and allowing the fungus to digest the nutrient material in the mixture over a period of time sufficient to grow hyphae and to allow the hyphae to form a network of interconnected mycelia cells through and around the discrete particles thereby bonding the discrete particles together to form a self-supporting composite material.
Where at least one of the inoculum and the mixture includes water, the formed self-supporting composite material is heated to a temperature sufficient to kill the fungus or otherwise dried to remove any residual water to prevent the further growth of hyphae.
The method may be carried out in a batchwise manner by placing the mixture and inoculum in a form so that the finished composite material takes on the shape of the form. Alternatively, the method may be performed in a continuous manner to form an endless length of composite material.
The method employs a step for growing filamentous fungi from any of the divisions of phylum Fungi. The examples that are disclosed focus on composites created from basidiomycetes, e.g., the “mushroom fungi” and most ecto-mycorrhizal fungi. But the same processes will work with any fungi that utilizes filamentous body structure. For example, both the lower fungi, saphrophytic oomycetes, the higher fungi, divided into zygomycetes and endo-mycorrhizal fungi as well as the ascomycetes and deutoeromycetes are all examples of fungi that posses a filamentous stage in their life-cycle. This filamentous stage is what allows the fungi to extend through its environment creating cellular tissue that can be used to add structural strength to a loose conglomeration of particles, fibers, or elements.
The invention also provides materials and composite materials, whose final shape is influenced by the enclosure, or series of enclosures, that the growth occurs within and/or around.
In accordance with the invention, the discrete particles may be of any type suited to the use for which the material is intended. For example, the particles may be selected from the group consisting of at least one of vermiculite and perlite where the composite material is to be used as a fire-resistant wall. Also, the particles may be selected from the group consisting of at least one of straw, hay, hemp, wool, cotton, rice hulls and recycled sawdust where composite material is to be used for insulation and strength is not a necessary criteria. The particles may also include synthetic insulating particles, such as, foam based products and polymers.
Referring to FIG. 1, the method of making a self-supporting structural material is comprised of the following steps.                0. Obtain substrate constituents, i.e. inoculum in either a sexual or asexual state, a bulking particle or a variety of bulking particles, a nutrient source or a variety of nutrient sources, a fibrous material or a variety of fibrous materials and water.        1. combining the substrate constituents into a growth media or slurry by mixing the substrate materials together in volumetric ratios to obtain a solid media while the inoculum is applied during or following the mixing process.        2. applying the growth media to an enclosure or series of enclosures representing the final or close to final geometry. The media is placed in an enclosure with a volume that denotes the composite's final form including internal and external features. The enclosure may contain other geometries embedded in the slurry to obtain a desired form.        3. growing the mycelia, i.e. filamentous hyphae, through the substrate. The enclosure is placed in an environmentally controlled incubation chamber as mycelia grows bonding the bulking particles and consuming the allotted nutrient(s).        3a. repeating steps 1-3 for applications in which materials are layered or embedded until the final composite media is produced.        4. removing the composite and rendering the composite biologically inert. The living composite, i.e. the particles bonded by the mycelia, is extracted from the enclosure and the organism is killed and the composite dehydrated.        5. completing the composite. The composite is post-processed to obtain the desired geometry and surface finish and laminated or coated.        
The inoculum is produced using any one of the many methods known for the cultivation and production of fungi including, but not limited to, liquid suspended fragmented mycelia, liquid suspended pore and mycelia growing on solid or liquid nutrient.
Inoculum is combined with the engineered substrate, which may be comprised of nutritional and non-nutritional particles, fibers, or other elements. This mixture of inoculum and substrate is then placed in an enclosure.
In step 3, hyphae are grown through the substrate, with the net shape of the substrate bounded by the physical dimensions of the enclosure. This enclosure can take on any range of shapes including rectangles, boxes, spheres, and any other combinations of surfaces that produce a volume. Growth can occur both inside the enclosure and outside of the enclosure depending on desired end shape. Similarly, multiple enclosures can be combined and nested to produce voids in the final substrate.
Other elements embedded with the slurry may also become integrated into the final composite through the growth of the hyphae.
The hyphae digest the nutrients and form a network of interconnected mycelia cells growing through and around the nutrients and through and around the non-nutrient particles, fibers, or elements. This growth provides structure to the once loose particles, fibers, elements and nutrients, effectively bonding them in place while bonding the hyphae to each other as well.
In step 4, the substrate, now held tightly together by the mycelia network, is separated from the enclosure, and any internal enclosures or elements are separated away, as desired.
The above method may be performed with a filamentous fungus selected from the group consisting of ascomycetes, basidiomycetes, deuteromycetes, oomycetes, and zygomycetes. The method is preferably performed with fungi selected from the class: Holobasidiomycete.
The method is more preferably performed with a fungus selected from the group consisting of:    pleurotus ostreatus     Agrocybe brasiliensis     Flammulina velutipes     Hypholoma capnoides     Hypholoma sublaterium     Morchella angusticeps     Macrolepiota procera     Coprinus comatus     Agaricus arvensis     Ganoderma tsugae     Inonotus obliquus 
The method allows for the production of materials that may, in various embodiments, be characterized as structural, acoustical, insulating, shock absorbing, fire protecting, biodegrading, flexible, rigid, water absorbing, and water resisting and which may have other properties in varying degrees based on the selection of fungi and the nutrients. By varying the nutrient size, shape, and type, the bonded bulking particle, object, or fiber, size, shape, and type, the environmental conditions, and the fungi strain, a diverse range of material types, characteristics and appearances can be produced using the method described above.
The present invention uses the vegetative growth cycle of filamentous fungi or the production of materials comprised entirely, or partially of the cellular body of said fungi collectively known as mycelia.
FIG. 2 shows a schematic representation of the life cycle of Pleareotus ostreatus, filamentous fungi. The area of interest for this invention is the vegetative state of a fungi's life cycle where a fungi is actively growing through the extension of its tube like hyphae.
In this Description, the following definitions are specifically used:
Spore: The haploid, asexual bud or sexual reproducing unit, or “seed”, of a fungus.
Hyphae: The thread-like, cellular tube of filamentous fungi which emerge and grow from the germination of a fungal spore.
Mycelium: The collection of hyphae tubes originating from a single spore and branching out into the environment.
Inoculum: Any carrier, solid, aerated, or liquid, of a organism, which can be used to transfer said organism to another media, medium, or substrate.
Nutrient: Any complex carbohydrate, polysaccharide chain, or fatty group, that a filamentous fungi can utilize as an energy source for growth.
Fruiting Body: A multicellular structure comprised of fungi hyphae that is formed for the purpose of spore production, generally referred to as a mushroom.
Fungi Culturing For Material Production
Methodology
Procedures for culturing filamentous fungi for material production.
All methods disclosed for the production of grown materials require an inoculation stage wherein an inoculum is used to transport a organism into a engineered substrate. The inoculum, carrying a desired fungi strain, is produced in sufficient quantities to inoculate the volume of the engineered substrates; inoculation volume may range from as low as 1% of the substances total volume to as high as 80% of the substrates volume. Inoculum may take the form of a liquid carrier, solid carrier, or any other known method for transporting a organism from one growth supporting environment to another.
Generally, the inoculum is comprised of water, carbohydrates, sugars, vitamins, other nutrients and the fungi. Depending on temperature, initial tissue amounts, humidity, inoculum constituent concentrations, and growth periods, culturing methodology could vary widely.